This should have been posted a couple weeks ago, but I have been quite busy...
Anyhow, after making the post below I changed out the power booster. No change. Every now & again the brake and ABS light comes on. The last time it came on I drove it directly to O'Reilly auto parts and left the truck running while they hooked up the OBD sensor. Instead of an answer it came up that the sensor hook up did not support an ABS code.
I can say this; IMHO it is an electronic something going on. I have done a couple other jobs recently which had me unhook the battery. I note that each time the electrical system is "reset", that the brake pedal is at the top and feels just like my '99. So, I have replaced the speed sensor at the rear diff, power booster, master cylinder & ABS controller. The only thing that makes a difference is unhooking the battery. What do I need to change out to fix this???
> Date: Mon, 12 Dec 2011 11:04:28 -0500
> From: <email@example.com>
> To: firstname.lastname@example.org
> Subject: Brake questions
> Good morning folks,
> Working on my son's '98 V-6 2WD Dak and am kinda stumped. Briefly, about a year ago the brake and ABS lights came on. At the same time the pedal took more effort, took more pedal before starting to work and when stopped you can feel the pedal pulsing like a spring snapping back on the pedal.
> We replaced the speed sensor at the rear end without success. I replaced the master cylinder without any change.
> I've taken it to a shop to have the code read and it said it couldn't read the ABS controller (located on the LF fender). I picked up a used controller at a junk yard and so far (about 2 weeks) the lights have stayed off. The pedal remains unchanged.
> I have performed the various tests outlined in the FSM and cannot locate the problem.
> The last test I performed was with a vacuum gauge to check the booster. According to the directions and diagram the vac. gauge is hooked into the vac. line with a "T" fitting. The vac. line into the T is clamped off, the engine shut off and you see how long vac. is held. A loss of 1" in 15 seconds is supposed to indicate a bad booster. When I perform this test, as soon as I clamp the vac. line the vac. goes to zero. It don't move when the truck is shut off either! Duh!!!
> Anyhow, I performed this same test on my '99 Dak which has no brake issues. The vac. gauge does the exact same thing.
> The truck stops fine, it just takes more pedal and more effort. Any ideas for me?
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